<template>
  <div>
    <!-- 评论列表 -->
    <div
     class="cmt-list"
     :class="{ 'art-cmt-container-1': !isShow, 'art-cmt-container-2': isShow }">
      <van-list
       v-model="loading"
       :finished="finished"
       finished-text="没有更多评论了，请发表评论"
       @load="onLoad"
       :immediate-check="false"
       >
        <!-- 评论的 Item 项 -->
        <div
         class="cmt-item"
         v-for="item in commentArr"
         :key="item.com_id">
          <!-- 头部区域 -->
          <div class="cmt-header">
            <!-- 头部左侧 -->
            <div class="cmt-header-left">
              <img :src="item.aut_photo" alt="" class="avatar" />
              <span class="uname">{{ item.aut_name }}</span>
            </div>
            <!-- 头部右侧 -->
            <div class="cmt-header-right">
              <van-icon name="like" size="16" color="red" v-if="item.is_liking" @click="likeFn(true, item)" />
              <van-icon name="like-o" size="16" color="gray" v-else @click="likeFn(false, item)" />
            </div>
          </div>
          <!-- 主体区域 -->
          <div class="cmt-body">
            {{ item.content }}
          </div>
          <!-- 尾部区域 -->
          <div class="cmt-footer">{{ timeAgo(item.pubdate) }}</div>
        </div>
      </van-list>
    </div>

    <!-- 发布评论 -->
    <div>
      <!-- 底部添加评论区域 - 1 -->
      <div class="add-cmt-box van-hairline--top" v-if="isShow === false">
        <van-icon name="arrow-left" size="0.48rem" @click="$router.back()" />
        <div class="ipt-cmt-div" @click="isShow = !isShow">发表评论</div>
        <div class="icon-box">
          <van-badge :content="totalCount === 0 ? '' : totalCount" max="99">
            <van-icon name="comment-o" size="0.53333334rem" @click="commentClickFn" />
          </van-badge>
          <van-icon name="star-o" size="0.53333334rem" />
          <van-icon name="share-o" size="0.53333334rem" />
        </div>
      </div>

      <!-- 底部添加评论区域 - 2 -->
      <div class="cmt-box van-hairline--top" v-else>
        <textarea v-fofo placeholder="友善评论、理性发言、阳光心灵" @blur="blurFn" v-model.trim="comText"></textarea>
        <van-button type="default" :disabled="comText.length === 0" @click="sendFn">发布</van-button>
      </div>
    </div>

  </div>
</template>

<script>
import { commentsListAPI, commentLikingAPI, commentDisLikingAPI, commentSendAPI } from '@/api/index.js'
import { timeAgo } from '@/utils/date.js'

export default {

  data () {
    return {
      offset: null, // 偏移量评论id
      commentArr: [], // 评论文章
      totalCount: 0, // 评论数量
      isShow: false, // 显示底部短/高的容器
      comText: '', // 发布评论的内容
      loading: false, // 加载状态
      finished: false, // 是否全部加载完成
      lastId: null // 请求更多分页的id
    }
  },
  async created () {
    const { data: res } = await commentsListAPI({
      source: this.$route.query.art_id
    })
    this.commentArr = res.data.results
    this.totalCount = res.data.total_count // 总评论
    this.lastId = res.data.last_id
    if (res.data.results.length === 0) {
      this.finished = true
    }
  },
  methods: {
    timeAgo,
    async likeFn (bool, item) {
      if (bool === true) {
        // 点击的是红心，调用取消点赞接口
        item.is_liking = false
        await commentDisLikingAPI({ target: item.com_id })
      } else {
        // 点击的不是红心，调用点赞接口
        item.is_liking = true
        await commentLikingAPI({ target: item.com_id })
      }
    },
    // 评论列表点击滚动事件
    commentClickFn () {
      // 需要设置window.scrollTo(0,文章高度)
      // const articleHeight = document.querySelector('.article-container').scrollHeight
      // window.scrollTo(0, articleHeight)
      // 真实DOM都在document(所以不再一个vue文件内), 也是可以获取的
      document.querySelector('.like-box').scrollIntoView({
        behavior: 'smooth'
      })
    },
    // 发布按钮点击事件
    async sendFn () {
      const { data: res } = await commentSendAPI({
        target: this.$route.query.art_id,
        content: this.comText
      })
      this.commentArr.unshift(res.data.new_obj)
      this.comText = ''
      this.totalCount++
      this.commentClickFn()
    },
    // 输入框失去焦点
    blurFn () {
      // 问题点击发布按钮，发现点击事件不执行-排除代码问题
      // 原因：高的评论容器，在页面点击发布的一瞬间，输入框失去焦点，被v-if和v-else移除了整个标签，导致点击事件没来的及执行
      // 解决：失去焦点，变量值最后执行
      setTimeout(() => {
        this.isShow = !this.isShow
      }, 0)
    },
    // 加载更多
    async onLoad () {
      if (this.commentArr.length > 0) {
        // 如果总数量没有10个
        if (this.lastId === null) {
          this.finished = true
          return
        }
        // 请求下一页数据
        const { data: res } = await commentsListAPI({
          source: this.$route.query.art_id,
          offset: this.lastId
        })
        this.commentArr = [...this.commentArr, ...res.data.results]
        this.totalCount = res.data.total_count // 总评论
        this.lastId = res.data.last_id
        if (res.data.lastId === null) {
          this.finished = true
        }
        this.loading = false
      } else {
        this.loading = false
      }
    }
  }
}
</script>

<style scoped lang="less">
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}
/*美化 - 文章详情 - 底部的评论页面 */
// 外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子 - 1
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    margin-left: 10px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}

.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子 - 2
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
